This invention relates to a multi-toroid transformer.
Referring to FIGS. 1a and 1b, high frequency, high voltage transformers 101, 102 are known from GB 0706197.1 which have multiple toroids 11, 12 for both primary and secondary circuit functions numbered 1 to Npc and 1 to Nsc respectively. A single turn tube 13 links these primary and secondary toroid groups. FIGS. 1a and 1b show a circuit diagram and a schematic drawing of such transformers respectively.
As power and/or operating requirements are increased a voltage Vloop on the single turn 13 can become sufficiently high that the primary core set 11 numbered 1 to Npc can be dispensed with if Vloop is a suitable voltage to connect directly to a power supply circuit output.
At a lower voltage it may also be possible to eliminate the set of primary closed magnetic circuits by making the loop more than a single turn. There is in fact no limit, in theory, to a number of turns that could be wound on the secondary core set so that the loop turns themselves match a required power supply voltage.
JP 11 176678 discloses a high voltage transformer comprising a plurality of modules connected in series each module comprising a transformer structure and a voltage amplification and rectifier circuit. The transformers of the modules are driven by a single turn primary winding which is apparently connected directly to a power supply.
GB 427,948 discloses a transformer with concentric single first and second windings on respective magnetic cores enclosed in a casing with a central post extending coaxially through the magnetic cores of the first and second windings such that the post and casing act as a secondary winding for the first winding and as a primary winding for the second winding, i.e. the post and casing form a common coupling winding.
U.S. Pat. No. 5,023,768 discloses a cylindrical tank with an axial hollow core such that secondary windings can be accommodated in the tank coaxial with the tank core. In one embodiment, multiple turns of insulated wire pass through the core and around an outer wall and end faces of the tank to form a primary winding. Alternatively, a single turn primary winding is formed from metal layers on the tank core, tank ends and outer walls.
U.S. Pat. No. 6,377,153 discloses a transformer for use in insulated switching power supply apparatus with a reduction of switching noise, in which cores are electrically connected by an electrically conductive housing which operates as a single-turn winding.